A wireless communication system is being extensively developed to provide various types of communication services such as voice, data, and the like. In general, the wireless communication system is a multi-access system capable of supporting communication with multiple users by sharing available radio resources (bandwidth, transmission power, etc.). Examples of the multi-access system include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier-frequency division multiple access (SC-FDMA) system, and the like.
IEEE (Institute of Electrical and Electronics Engineers) 802.16 standard provides techniques and protocols to support a broadband wireless access. Standardization started from 1999 and IEEE 802.16-2001 was approved in 2001. It is based on a single carrier physical layer called ‘WirelessMAN-SC’. Later, besides the ‘WirelessMAN-SC’, ‘WirelessMAN-OFDM’ and ‘WirelessMAN-OFDMA’ were added to a physical layer in IEEE 802.16a standard approved in 2003. After the IEEE 802.16a standard was completed, a revised IEEE 802.16-2004 standard was approved in 2004. IEEE 802.16-2004/Cor1 (referred to as ‘IEEE 802.16e’, hereinafter) was finalized in the form of ‘corrigendum’ in 2005 in order to resolve and correct bugs and errors of the IEEE 802.16-2004 standard. A standard based on the IEEE 802.16-2004/Cor1 is called IEEE802.16e or WiMAX. Currently, the IEEE 802.16 broadband wireless access working group is conducting standardization of an IEEE 802.16m, a new technical standard, based on the IEEE 802.16e.
The IEEE 802.16 wireless communication system provides a high speed multimedia communication service to users beyond the conventional voice and packet data communication service. The multimedia communication service is a service for simultaneously transmitting data packets to multiple user equipments (UEs), which is called by other names such as broadcast/multicast service, multimedia broadcast multicast service (MBMS), multicast and broadcast service (MBS), enhanced multicast broadcast service (EMBS), or point-to-multipoint service. In the description of the present invention, such terms are mixedly used. In the MBS, an IP multicast-based service, UEs receive the same multimedia data by sharing resources required for transmission of data packets. Thus, resource efficiency can be enhanced.
MBS can be classified into two types of services. The first type of MBS is based on a single-base station (BS) access scheme in which the MBS is provided by a single BS in a single cell. The examples of this type of service include a mobile TV, emergency alert, home network, intra-office broadcasting, and the like. The second type of MBS is based on a multi-BS access scheme in which several BSs form a single MBS zone to provide an MBS service. Namely, several BSs are allocated the same burst from an MBS server in multiple cells within the same MBS zone by using a single MBS zone ID and provide an MBS service. Thus, a service continuity and macro-diversity gain can be attained without performing handover in case of an inter-cell movement including BSs.
Control information for the MBS is transmitted via a multicast service control channel (MSCCH). In the description of the present invention, the MSCCH may be mixedly used with a multicast broadcast control channel, an MBS MAP, an enhanced multicast broadcast service (E-MBS) MAP, and the like. If every control information related to the two types of MBSs is transmitted via a single MSCCH, the operation would be simple. In this case, however, information irrelevant to a corresponding cell may be received, a signaling overhead is large, and there is a limitation in a modulation and coding scheme (MCS) level. Thus, a method for effectively transmitting the control information for the MBS is required.